In many applications, it is desirable to design connectors so their contact assemblies divert to ground any high voltage pulses induced by high energy electromagnetic pulses or static electricity, and also filter out frequency signals of unwanted frequencies induced by electromagnetic energy in the environment. Such unwanted signals are often referred to as EMP (electromagnetic pulse, ESD (electrostatic discharge), EMI (electromagnetic interference), and RFI (radio frequency interference), all of which may be referred to as EMX. While diodes and capacitive/capacitive-inductive filters have been connected to contacts of connectors to cancel the effects of EMX, the resulting contact assemblies have been relatively complex, which increases their cost, and have been relatively cumbersome. The cumbersome contact assemblies are difficult to replace by simply pulling out a defective one (which may be due to mechanical or electrical damage) from a long thin hole in the connector and inserting a new one in its place.
U.S. Pat. No. 4,747,789 by Gliha shows a connector with a diode and filter connected to a signal conductor, but the arrangement, especially the filter, is cumbersome, having a diameter many times greater than that of the signal conductor and not capable of easy replacement in the same manner as a simple signal contact. U.S. Pat. No. 4,746,310 by Morse shows an attempt to make a relatively compact contact assembly, with the diode lying in a notch in the signal conductor and with the inductor comprising a ferrite sleeve closely surrounding the signal conductor. However, the connector requires two large capacitors which are not part of the contact assembly so that replacement of the contact assembly does not replace the capacitors.
A contact assembly which minimized the number of components while providing effective filtering and transient suppression, and which resulted in a compact contact assembly with all filtering and suppression elements included in a thin and rugged assembly that could be easily inserted and removed from a small diameter hole in the connector for in-field replacement, would be of considerable value.